<template>
  <div class="xtx-city" ref="target">
    <div class="select" @click="toggle()" :class="{ active: visible }">
      <span v-if="!fullLocation" class="placeholder">{{ placeholder }}</span>
      <span v-else class="value">{{ fullLocation }}</span>
      <i class="iconfont icon-angle-down"></i>
    </div>
    <div class="option" v-if="visible">
      <div v-if="loading" class="loading"></div>
      <template v-else>
        <span class="ellipsis" @click="changeItem(item)" v-for="item in currList" :key="item.code">{{ item.name
        }}</span>
      </template>
    </div>
  </div>
</template>
<script  setup >
import { computed, reactive, ref } from 'vue'
import { onClickOutside } from '@vueuse/core'
// import getCityData from "@/utils"
import axios from "axios"
const props = defineProps({
  fullLocation: {
    type: String,
    default: ''
  },
  placeholder: {
    type: String,
    default: '请选择配送地址'
  }
})

const emit = defineEmits(["change", "changeResult"])


// 显示隐藏数据
let visible = ref(false)

// 所有省市区数据
let allCityData = ref([])
// 正在加载数据
let loading = ref(false)

// 提供打开和关闭函数
const open = () => {
  visible.value = true
  // 获取地区数据
  loading.value = true
  getCityData().then(data => {
    allCityData.value = data
    loading.value = false
  })
  // 清空之前选择
  for (const key in changeResult) {
    changeResult[key] = ''
  }
}
const close = () => {
  visible.value = false
}
// 提供一个切换函数给select使用
const toggle = () => {
  visible.value ? close() : open()
}
// 实现点击组件外部元素进行关闭操作
const target = ref(null)
onClickOutside(target, () => {
  // 参数1：监听那个元素
  // 参数2：点击了该元素外的其他地方触发的函数
  close()
})

// 实现计算属性：获取当前显示的地区数组
const currList = computed(() => {
  // 默认省一级
  let list = allCityData.value
  // 可能：市一级
  if (changeResult.provinceCode && changeResult.provinceName) {
    list = list.find(p => p.code === changeResult.provinceCode).areaList
  }
  // 可能：县地区一级
  if (changeResult.cityCode && changeResult.cityName) {
    list = list.find(c => c.code === changeResult.cityCode).areaList
  }
  return list
})

// 定义选择的 省市区 数据
const changeResult = reactive({
  provinceCode: '',
  provinceName: '',
  cityCode: '',
  cityName: '',
  countyCode: '',
  countyName: '',
  fullLocation: ''
})
// 当你点击按钮的时候记录
const changeItem = (item) => {
  if (item.level === 0) {
    // 省
    changeResult.provinceCode = item.code
    changeResult.provinceName = item.name
  }
  if (item.level === 1) {
    // 市
    changeResult.cityCode = item.code
    changeResult.cityName = item.name
  }
  if (item.level === 2) {
    // 地区
    changeResult.countyCode = item.code
    changeResult.countyName = item.name
    // 完整路径
    changeResult.fullLocation = `${changeResult.provinceName} ${changeResult.cityName} ${changeResult.countyName}`
    // 这是最后一级，选完了，关闭对话框，通知父组件数据
    close()
    emit('change', changeResult)
  }
}

const getCityData = () => {
  // 数据：https://yjy-oss-files.oss-cn-zhangjiakou.aliyuncs.com/tuxian/area.json
  // 1. 当本地没有缓存，发请求获取数据
  // 2. 当本地缓存，取出本地数据
  // 返回promise在then获取数据，这里可能是异步操作可能是同步操作
  return new Promise((resolve, reject) => {
    // 约定：数据存储在window上的cityData字段
    if (window.cityData) {
      resolve(window.cityData)
    } else {
      const url =
        'https://yjy-oss-files.oss-cn-zhangjiakou.aliyuncs.com/tuxian/area.json'
      axios.get(url).then((res) => {
        // 缓存
        window.cityData = res.data
        resolve(res.data)
      })
    }
  })
}

</script>
<style scoped lang="less">
.xtx-city {
  display: inline-block;
  position: relative;
  z-index: 400;

  .select {
    border: 1px solid #e4e4e4;
    height: 30px;
    padding: 0 5px;
    line-height: 28px;
    cursor: pointer;

    &.active {
      background: #fff;
    }

    .placeholder {
      color: #999;
    }

    .value {
      color: #666;
      font-size: 12px;
    }

    i {
      font-size: 12px;
      margin-left: 5px;
    }
  }

  .option {
    width: 542px;
    border: 1px solid #e4e4e4;
    position: absolute;
    left: 0;
    top: 29px;
    background: #fff;
    min-height: 30px;
    line-height: 30px;
    display: flex;
    flex-wrap: wrap;
    padding: 10px;

    >span {
      width: 130px;
      text-align: center;
      cursor: pointer;
      border-radius: 4px;
      padding: 0 3px;

      &:hover {
        background: #f5f5f5;
      }
    }

    .loading {
      height: 290px;
      width: 100%;
      background: url(~@/assets/img/loading.gif) no-repeat center;
    }
  }
}
</style>
